1. Field of the Invention
The present invention relates to an apparatus and method for managing data transfer in a voice over Internet protocol (VoIP).
2. Description of the Related Art
First, a session initiation protocol (SIP) and an H.323, a representative protocol for a voice over Internet protocol (VoIP) technology and a VoIP call, will now be described.
VoIP means a series of communication service technologies which convert voice data into data packets of an Internet protocol to enable a voice call like a telephone call in a general telephone network (e.g., a public switched telephone network (PSTN)).
The SIP is a control protocol of application layer that creates, modifies and releases an end to end multimedia session. Herein, the multimedia session includes an Internet telephone call. Such SIP is nothing but a protocol setting a session. VoIP system uses a session description protocol (SDP) to clarify a method for end to end data transfer. Such SDP includes a title and a purpose of session, a media description to be used for session, and information required for media transport (address, port, format, etc.).
H.323 describes a method for construction of VoIP system using various protocols of Internet Telecommunication Union (ITU). Such H.323 defines a process such as signaling conversion, media transport, call set-up, etc. For example, for performance of the call set-up, H.225.0 is used, and for voice and image media transport, real-time protocol (RTP)/RTP control protocol (RTCP) is used.